Over the past few years, rapid technological advances have occurred in automatic manufacturing. Among these are improvements to robotic quick change tooling systems, which render robots more cost effective by increasing their flexibility and versatility, and by reducing the "down-time" in which the robot is inoperative during changing or inspection of tools.
For example, U.S. Pat. No. 4,551,903 to Bisiach granted Nov. 12, 1985 shows a coupling device including a hollow cylinder 16, a central body 19 and a crown gear 40, mounted to a tool holder head 10 at the end of a robot's arm. The arm is moved to carry the coupling device to a tool connection plate held by a magazine 90. A rack 50 is mounted on the magazine, and moves vertically to rotate crown gear 40 into a locking position. This secures the tool to head 10, and releases the connection plate from the magazine.
A tool holder, shown in U.S. Pat. No. 4,525,918 to Puritz granted July 2, 1985 includes a sleeve 3 and a component 25 having a conical shaft 26 that fits into a conical bore 2 in the sleeve. The shaft also has a locking groove 29, with locking bolts 12 mounted in the sleeve and extending into the locking groove to secure the shaft. Centering pins 4 align the sleeve and component.
Yet another tool changing apparatus is shown in U.S. Pat. No. 4,046,263 to Cwycychyn et al granted Sept. 6, 1977. A support assembly 28, mounted to a manipulator arm 20, has a pyramid-shaped projection 38 that extends into an opening 42 in a plate 44 connected to a tool. A wedge member 36 on the support assembly slides downward into an opening in projection 38 to secure the plate to the arm.
While these and other tool changing systems are often satisfactory, they do not adequately meet the need for a system that allows rapid changing of tools,yet withstands high loads and protects the tool from falling from the robot in the event of a power failure. A tool's falling off of a robot arm may seem like a trivial event, until the expense of repairing or replacing such tooling is considered. Another concern is the damage that can occur to the robotic arm, tools, or a workpiece being manipulated by the tools, should the robot arm or tool contact a workpiece at a point other than that desired, for example in the course of finishing a workpiece or drilling a hole in the workpiece.
Therefore, it is an object of the present invention to provide apparatus for interchangeably supporting tools with respect to a robotic arm, and for permitting rapid changing of the tools.
Another object of the invention is to provide a means for supporting a tool on a robot arm, which can handle heavy payloads and can positively retain the tool in the event of interruption of power to the robotic arm.
Yet another object of the invention is to provide apparatus to support a tool on a robot arm, which permits a slight deviation of the robot arm from an ideal position, but prevents operation of the tool, should the deviation from an ideal arm position be too severe.